1. Field of the Invention
The present invention relates to a communication apparatus that communicates with an external apparatus, a control method, and a computer-readable recording medium.
2. Description of the Related Art
At present, there are suggested communication systems which comply with the High Definition Multimedia Interface (HDMI, registered trademark) standard (hereinafter referred to as the “HDMI systems”). The HDMI system includes a source apparatus that transmits video data and audio data, and a sink apparatus that has a display apparatus to display video data received from the source apparatus.
In an HDMI system, a user can cause the sink apparatus to display video data reproduced from the source apparatus, and view desired video data.
Japanese Patent Application Laid-Open No. 2007-078980 discusses that, in the above HDMI system, the source apparatus acquires Extended display identification data (EDID) from the sink apparatus, according to a Hot Plug Detect (HPD) signal detected from the sink apparatus. Based on the acquired EDID, the source apparatus also transmits video data that the sink apparatus can output.
If video data received from the source apparatus is not compatible with the EDID description, the sink apparatus does not output (or display) video data received from the source apparatus, even after the sink apparatus receives video data from the source apparatus.
In such a case, even if the source apparatus continues to transmit video data to the sink apparatus, the source apparatus merely consumes extra power, as the sink apparatus does not display the video data transmitted from the source apparatus.
When an HPD signal is on, the sink apparatus outputs (displays) video data compatible with the description of the EDID received from the source apparatus, after transmitting the EDID to the source apparatus in response to an EDID request from the source apparatus.
Therefore, after the sink apparatus outputs (displays) video data received from the source apparatus, the source apparatus needs to acquire again the EDID of the sink apparatus so as to cause the sink apparatus to output video data received from the source apparatus, even if the source apparatus has already acquired the EDID from the sink apparatus.
In such a case, after acquiring again the EDID of the sink apparatus, the source apparatus analyzes the acquired EDID. The source apparatus then generates video data compatible with the description of the EDID of the sink apparatus, and transmits the video data to the sink apparatus. Therefore, there is a delay in outputting (displaying) the video data from the source apparatus by the sink apparatus.